A combine harvester, or a combine, is a machine that is used to harvest grain crops. The objective is to complete several processes, which traditionally were distinct, in one pass of the machine over a particular part of the field. Among the crops that may be harvested with a combine are wheat, oats, rye, barley, corn, soybeans, flax or linseed, and others. The waste (e.g., straw) discharged on the field includes the remaining dried stems and leaves of the crop which may be, for example, chopped and spread on the field as residue or baled for feed and bedding for livestock.
A combine harvester cuts crop using a wide cutting header. The cut crop may be picked up and fed into the threshing and separating mechanism of the combine, typically consisting of a rotating threshing rotor or cylinder to which grooved steel bars, commonly referred to as rasp bars or threshing elements, may be bolted. These rasp bars thresh and aid in separating the grains from the chaff and straw through the action of the drum against the concaves, i.e., shaped “half drum,” that may also be fitted with steel bars and a meshed grill, through which grain, chaff and smaller debris may fall, whereas the straw, being too big or long, is carried through to the outlet. The chaff, straw, and other undesired material are returned to the field via a spreader mechanism.
In an axial flow combine, this threshing and separating system serves a primary separation function. The harvested crop is threshed and separated as it is conveyed between a longitudinally arranged rotor and the inner surface of an associated chamber comprising threshing and separating concaves, and a rotor cage or cover. The cut crop material spirals and is conveyed along a helical path along the inner surface of the chamber until substantially only larger residue remains. When the residue reaches the end of the threshing drum, it is expelled out of the rear of the combine. Meanwhile, the grain, chaff, and other small debris fall through the concaves and grates onto a cleaning device or shoe. For ease of reference, this smaller particulate crop material that contains the grain and chaff is referred to as threshed crop. The grain still needs to be further separated from the chaff by way of a winnowing process.
Clean grain is separated out of the threshed crop be way of a flat oscillating cleaning system that can include a chaffer and sieves. Generally, the cleaning system operates by mechanical and pneumatic methods; blowing air through the threshed crop to winnow the chaff and then sieving the grain to separate the grain from other particulates. Clean grain that is separated from residue via the sieves is typically transported to a grain tank in the combine for temporary storage. The grain tank is typically located atop the combine and loaded via a conveyer that carries clean grain collected in the cleaning system to the grain tank.
In normal operation, an operator of a combine tries to optimize the performance of the combine by making various adjustments to operational parameters of the combine and then trying to quantify the positive/negative effect the change had. Various functional components or parameters of a combine can be adjusted by the operator, and there impacts on the operating efficiency of the combine can be monitored. For example, the forward speed of the combine can be controlled by the operator. However, as speed increases, so too does the amount of material collected. However, once the operator reaches a certain forward speed, an amount of material lost begins to increase dramatically. The threshing process can only handle so much material regardless of the forward speed of the combine, and at a certain speed collected grain begins to be lost as the thresher cannot keep up with the amount of material collected. A loss sensor measures the amount of lost material and an indicator in the cab of the combine may display this measured amount to the operator via a gauge reading or a graph on a digital display. Additionally, an audible alarm may sound indicating the high loss levels to the operator. The operator may then adjust the speed such that the amount of grain collected is balanced against the amount of grain being lost, thus running the combine at the most efficient forward speed. Additional functional components such as the sieves, blowers, grates, and other components can be adjusted as well, impacting the overall efficiency of the combine.
The visual indicators in the cab have several inherent drawbacks. For example, the indicators are only showing information in real-time and may be constantly fluctuating as the density or type of crop being harvested changes. In order to provide a historical reading over time, the operator must watch the monitors and mentally assign a value to the average readout level. This process must be done almost concurrently for many different parameters. The process is therefore prone to errors and the accuracy is subjective and limited in scope.
Another means for collecting historical readings is to physically inspect samples of harvested material in the field to determine any associated loss. This process is time consuming and requires special procedures to get good data representative of the combine performance.